Perl may be copied only under the terms of either the Artistic License
or the

GNU General Public License, which may be found in the Perl 5 source kit.
Complete documentation for Perl, including FAQ lists, should be found on
this system using "man perl" or "perldoc perl". If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.
Create a test file:
2018-10-20 20:59:22 dpchrist@vstretch ~/sandbox/perl
$ touch testfile
Your program:
2018-10-20 20:57:38 dpchrist@vstretch ~/sandbox/perl
$ vi File-stat.pl
#!/usr/bin/perl -w
use strict;
use warnings::unused;
use File::stat;
use File::Spec;
my $last_update_time;
$last_update_time = ( stat("testfile") )[9];
printf("%d\n",$last_update_time);
Compile it:
2018-10-20 21:00:26 dpchrist@vstretch ~/sandbox/perl
$ perl -c File-stat.pl